Brother Mine
by Kirii
Summary: Movieverse Sunstreaker and Sideswipe were separated during an attack by Decepticons while en route to Earth. After coming to Earth, Sunstreaker is plagued by thoughts of what might have happened to his twin, but those thoughts are soon interrupted.


**Title:** Brother Mine  
**Rating:** R  
**Pairings:** Sunstreaker/Sideswipe, with brief mention of Prowl/Jazz  
**Summary:** [Movie-verse Sunstreaker and Sideswipe were separated during an attack by Decepticons while en route to Earth. After coming to Earth, Sunstreaker is plagued by thoughts of what might have happened to his twin, but those thoughts are soon interrupted when a certain mech appears in the wash racks with him.  
**Notes:** This was spawned from what's going on with my Sunstreaker at livetransfanfic on livejournal. This is what happens when Kirii lacks a Sideswipe to play with! Anyways, I apologize for any OOCness. This is my first time writing them in this way.  
**Disclaimer:** The last time I tried to own them, I was left in the middle of the ocean, floating around in a beer barrel. I really don't want to talk about how I got back to the States.

**-Brother Mine-**

Sunstreaker stood in the wash racks, letting the water pummel his body as he slowly polished his bright yellow armor. He had never been so long without his twin beside him and it hurt to be separated from Sideswipe. The yellow mech's spark ached at the various thoughts that ran through his processor, thoughts of what might have happened to his brother when they had gotten separated in battle.

The spark bond that Sunstreaker shared with his twin was unique to them; while other mechs shared spark bonds, like with Prowl and Jazz, that were the result of a bonding of two sparks, Sunstreaker and Sideswipe had always had one half of the same spark, which had split during their creation. Their sparks were their links to each other from the very moment they were first brought online as sparklings.

Sunstreaker had always been able to feel his brother's presence within him. He could always feel Sideswipe through their spark bond, feel his brother's emotions and share them. Their bond was always there as a reassurance that his twin was by his side. Without it, Sunstreaker was lost, missing a part of himself that his brother completed. Without his brother, he wasn't himself and if he wasn't himself, who was he?

For the first time in his life, Sunstreaker was alone. When he and Sideswipe received the message from Optimus Prime that the other Autobots were waiting on Earth, they'd gone together into space to find Earth and the others. Then they'd been attacked by a group of Decepticons that still wandered and they'd been separated. Sunstreaker had been fighting Thundercracker when he was thrown off and knocked off-line for an unknown period of time. When he'd awoken, he was far from the battle site… and he was alone. He opened a communication line and called out to his brother; he received no reply. Sideswipe was out of range. Or the Decepticons had overpowered the other twin. The very thought had made Sunstreaker's spark ache like had never done so before.

He'd spent joors calling for his brother. He couldn't feel his brother, couldn't sense him at the other end of the bond their sparks shared. Never had he ever felt such fear; yes, he admittedly would be worried if his twin was badly damaged in battle, but when he couldn't even feel his brother's presence in his spark, that wasn't just anxiety. What he had felt when he couldn't sense his brother was complete and unrestrained fear.

When he arrived to Earth, the other Autobots were startled that Sideswipe was not with him; they rarely saw the twins apart and to see only one of them arrive to the planet they now called home was unsettling. Ratchet had questioned on Sideswipe's location, only to receive a growl and short explanation that they'd gotten separated in battle. It was soon obvious to the others that asking Sunstreaker anything about his twin was not a good idea, for the yellow Lamborghini-disguised Autobot would sink into a nastier mood than his usual one and Optimus Prime deemed, after the second time Ratchet had to repair the recently-arrived Hot Rod, that no one was to mention the missing Sideswipe.

Sunstreaker had left to the wash racks shortly after Optimus made this decree. He needed some time away from the other Autobots on the base they'd built on Earth. It was as he washed and polished his armor after the fight with Hot Rod that he began to dwell again on what might have happened to his twin.

Absorbed in dismal thoughts of his brother's fate, Sunstreaker didn't notice when the doors to the wash room hissed open. He wasn't even aware that another mech approached him. In fact, the only thing that alerted him at all that he was no longer alone was a pair of arms that wrapped around his waist and a familiar feeling returned to his spark. Sunstreaker gave a start and turned his head to meet the optics of a very familiar mech.

"Sideswipe?" he asked softly, voice wavering as he spoke his twin's name.

"Did you miss me?" Sideswipe grinned.

Sunstreaker managed somehow to turn around in his brother's arms to face Sideswipe. For a while, he looked as though he wouldn't be able to answer. Then, after a breem of silence from the yellow twin…

"YOU FRAGGING GLITCHER!!"

Both twins fell to the floor of the wash room as Sunstreaker hit Sideswipe while the red twin still held to his waist. Sideswipe let out a sharp cry at the hit and another when he hit the floor. He opened his mouth to curse at his brother for hitting him but was cut off when Sunstreaker pressed his mouth to his own in a kiss. Surprised, he allowed his brother to kiss him with unexpected gentleness. The kiss lasted only a few short breems, but it relayed to him all the fear and sadness that his brother had felt during their separation.

"Slag it, Sides," Sunstreaker muttered, pulling away. "You scared me."

Sideswipe knew that Sunstreaker was always more open with him than he was with any other mech, but this was the first time that he'd ever heard his strong, brash and cold brother admit to being afraid. He felt Sunstreaker put his arms around him and hold tightly. His brother was genuinely scared and it was because of him. Cautiously, he reached with one hand and began to stroke a sensitive spot on Sunstreaker's armor, just below his shoulders, in an attempt to give some comfort to his twin.

"I thought you were gone," Sunstreaker continued, voice soft.

"You know I'd never leave you," Sideswipe told his brother.

Sunstreaker gave a weak laugh. Despite the frequent fights that the two got in, they truly loved each other. They rarely showed it when anyone else was present, but in the privacy of each other, they let everything out. While they wouldn't let anyone else know it, they meant the worlds to each other. After being so long without his twin, Sunstreaker realized just how much he needed Sideswipe with him. He leaned in and kissed his brother once again.

Sideswipe returned the kiss this time, shifting his arms from their place around Sunstreaker's waist and moving upwards. He felt his brother give a shiver as his fingers crossed a particularly sensitive spot and their sparks both gave off a burst of heat. Sunstreaker's own hands began to seek out sensitive spots on his brother; it was a little more difficult with the red armor that Sideswipe now sported after coming to Earth, but he still knew the general areas that made his brother's circuits rage.

The kiss broke and Sunstreaker shifted, pressing his lips against Sideswipe's neck, sending a short burst of electricity through his twin's body. He heard a moan escape his brother and pressed his chassis against Sideswipe's, letting the warmth from his body flow to the other and his brother's warmth flood into his.

"S-Sunny," Sideswipe managed, circuits already surging with energy. "Th-this isn't the place…"

"I don't care," Sunstreaker replied, letting his hands explore his brother's body. His fingers ghosted over the bumper on Sideswipe's chassis, calling forth another moan from his brother.

"S-Sunstreaker…"

The yellow twin bent his fingers into a small opening in his twin's armor, letting them brush against a sensitive circuit. Sideswipe let out a sharp gasp as his systems surged at the touch. In retaliation to his brother's ministrations, he stroked the spot behind his brother's audios that made Sunstreaker shiver and let out his own pleasured sounds. Sunstreaker's body curled against his brother's and he leaned down to place his lips again to Sideswipe's.

"Sides…don't leave me alone again…" he murmured before pressing into the kiss.

Sideswipe cradled his brother's head in his hand as they kissed. _//Never.//_

_//I love you, bro.//_

Sunstreaker felt the smile on his twin's lips. _//I love you, too, Sunny.//_

Their hands explored each other's body, gaining speed and desperation as they continued. Before long, Sunstreaker opened his spark casing, offering his half of their shared spark to his twin. Sideswipe opened his own, letting his spark touch with his brother's. The waves of energy that pulsed from the two sparks washed over their bodies, pushing their systems to overload. Sunstreaker's spark circled Sideswipe's briefly before closing in and the two halves merged to create the original spark that had long ago split to give life to the twins.

Cries escaped both brothers at the rejoining of their sparks. Sideswipe put his legs around Sunstreaker, clinging to him as Sunstreaker clung back. They were together, as they should be. After the long separation, this is what they needed; to know that they were once again one with each other. They had always had their differences and their fights, but when they were together, that was the most perfect thing to them. For the longest time, since the war began, each brother had been all the other had, all they needed. Sunstreaker had Sideswipe and Sideswipe had him.

They called for each other as they hit their overload together, their circuits surging with unrestrained energy from their sparks. They held onto each other as their sparks pulled apart and retreated into their respective chambers. After a brief moment, each twin activated their internal cooling systems, circulating air through their bodies to cool down. Sunstreaker slowly got off Sideswipe and sat up, pulling his twin up with him.

"What took you so long to come?" he asked.

"What does it matter?" Sideswipe replied. "I came."

Sunstreaker shuttered his optics and pulled his brother into an embrace. "Slagger," he muttered.

"I love you, too, bro," Sideswipe smirked, putting his arms around his twin in return.

_**Fin**_

_For my first finished TF smut, I think that wasn't half bad. o.o Nowhere near as good as smut I've written in the past, but I blame Aromatherapy for sapping all my smut skills. _


End file.
